The development of a 20-item semantic differential assessment instrument for measuring student attitudes toward the subject of chemistry is described (Attitude toward the Subject of Chemistry Inventory-ASCI). Instrument subscales and survey items pertain to interest and utility, anxiety, intellectual accessibility, emotional satisfaction, and fear. Detailed information on validity is provided by means of exploratory factor analysis, comparisons between different populations of students (general chemistry, peer leaders, chemistry majors), and comparisons with course performance. Reliability is established by estimation of internal consistency of subscales and retesting correlation. The instrument is useful for assessing student attitude for any curriculum setting for longitudinal change or intercomparison of groups. Specific application in an inquiry-based, nonmajors chemistry course is described. (Contains 5 tables and 1 figure.)